A job is not one material.

A paint manufacturer will size your paint. It will not tell you about the primer, the tape or the spackle, and it certainly will not mention the drywall underneath. Here is what a whole job takes, in the order you buy it, with the arithmetic for each part.

1. Refinish a deck

   Cleaning and staining an existing deck, railings and steps.

   • Stain gallons, and rough wood drinks about three times what smooth does
   • Cleaner or brightener sized off the stain area, one application
   • Replacement boards counted, not calculated

   One calculator covers the material that costs the most and varies the most. The rest follow its area.

2. Finish a room

   Bare studs to painted walls: board, tape, mud, then paint.

   • Drywall sheets, plus the mud, tape and screws everyone forgets
   • Paint gallons, and the coverage number decides it, not the room size
   • Wallpaper if you are papering instead, rolls turn on the pattern repeat

   All three take the same room dimensions. Measure once, then run whichever ones the job needs.

3. Plant a bed

   Preparing the ground, edging a new bed, laying fabric and topping it with mulch.

   • Topsoil and compost the two inches worked in before anything is planted
   • Mulch cubic yards or bags, and depth is the whole calculation
   • Gravel if it is a path or a dry bed instead, tons depend on the stone
   • Edging and fabric both sized off the bed perimeter and area

   Mulch and gravel take the same area and depth, so a bed and the path beside it are one measurement.

4. Put up a fence

   Setting posts in concrete along a run, with a gate.

   • Posts and concrete posts for the run, plus the bags that set them
   • Gravel the drainage base in each hole, which the bag math assumes
   • Rails and pickets counted off the span, not calculated

   The fence calculator already assumes a gravel base in every hole. This is where that gravel comes from.

5. Lay a patio

   A compacted base, a slab poured on top of it, and a tiled finish if you want one.

   • Gravel base tons, and the tonnage depends on the stone, so ask your supplier for its density
   • Concrete bags, and it tells you when the pour is big enough to call a truck instead
   • Outdoor tile only if you are tiling over the cured slab: tiles first, then boxes
   • Forms and stakes cut to the slab perimeter, counted rather than calculated

   Three calculators, one measurement. The slab area drives the base underneath it and the tile over it, so measure once and run them in order.

6. Reseed a patchy lawn

   Overseeding thin grass rather than starting from bare soil.

   • Grass seed pounds, and overseeding takes about a third of the new-lawn rate
   • Starter fertilizer pounds of product, which is not the pounds of nitrogen the label talks about
   • Topsoil or compost a quarter inch topdressed over the whole lawn, which is far less than most people buy

   Pick overseeding rather than new lawn in the calculator or you will buy three times the seed, grow a thinner lawn, and pay for both.

Every material above with a link has a calculator behind it that shows its formula and names the spec sheet its numbers came from. The ones without a link are counted rather than calculated, and we would rather say so than invent a rule for them.